This chapter provides an overview of the book and makes an argument for why it is important to study and understand the experiences of people with hearing loss (PHL) and their communication partners (CPs) longitudinally in the form of a timeline. The chapter starts with some background information to hearing loss and its broader consequences. Some discussion will be presented regarding how is hearing loss is understood. Theoretical frameworks that will form the foundation for this book will be discussed. The concepts of outcome measurement and process evaluation will be introduced in relation to research on the patient journey highlighting the human dynamics of hearing loss.